Animal control systems are known in which a transmitter generates a coded signal that is radiated by a wire loop antenna which is buried a few inches underground and which defines an area in which the animal, typically a dog, is to be contained or from which the animal is to be restricted. A receiver mounted on a collar placed around the neck of the animal includes one or more electrodes which are in physical contact with the skin of the animal. As the animal wearing the receiver approaches the wire loop antenna, the receiver detects the radiated signal, and if the received signal meets one or more qualifying standards, a stimulus is applied to the animal. The stimulus may be in the form of an audible alert and/or an electric shock administered to the animal through the electrodes. Examples of such systems are shown in U.S. Pat. Nos. 5,465,687, 5,353,744, 6,360,698 and 6,367,435, all assigned to the Assignee of the present invention and incorporated herein by reference.